About

Christopher Jarzynski is a Distinguished University Professor in the Department of Chemistry and Biochemistry at the University of Maryland. His research group focuses on statistical mechanics and thermodynamics at the molecular level, with particular emphasis on far-from-equilibrium phenomena. His work includes applying statistical mechanics to biophysical problems, analyzing artificial molecular machines, developing efficient numerical schemes for estimating thermodynamic properties of complex systems, and exploring the relationship between thermodynamics and information processing. Additionally, his interests extend to dynamical systems, quantum thermodynamics, and quantum and classical shortcuts to adiabaticity. Dr. Jarzynski's educational background includes an A.B. in Physics with high honors from Princeton University and a Ph.D. in Physics from the University of California, Berkeley. His professional experience encompasses roles at Los Alamos National Laboratory, the University of Maryland as an associate professor and professor, and director of the Institute for Physical Science and Technology. He has received numerous awards and recognitions, such as the Lars Onsager Prize, Fellowships from the American Physical Society and the American Academy of Arts and Sciences, and membership in the National Academy of Sciences. His contributions to the field include developing theoretical tools for understanding nonequilibrium behavior, constructing models for complex phenomena, and advancing the understanding of thermodynamics at small scales and in information processing.

Research topics

• Physics
• Statistical physics
• Computer science
• Classical mechanics
• Mathematics

Selected publications

• Work and heat exchanged during sudden quenches of strongly coupled quantum systems

  ArXiv.org · 2025-02-26

  preprintOpen access

  How should one define thermodynamic quantities (internal energy, work, heat, etc.) for quantum systems coupled to their environments strongly? We examine three (classically equivalent) definitions of a quantum system's internal energy under strong-coupling conditions. Each internal-energy definition implies a definition of work and a definition of heat. Our study focuses on quenches, common processes in which the Hamiltonian changes abruptly. In these processes, the first law of thermodynamics holds for each set of definitions by construction. However, we prove that only two sets obey the second law. We illustrate our findings using a simple spin model. Our results guide studies of thermodynamic quantities in strongly coupled quantum systems.

  PublisherOA PDFDOI

• Decoherence and Brownian motion of a polarizable particle near a medium

  Physical review. A/Physical review, A · 2025-09-18

  articleOpen access

  Optically levitated nanoparticles are ideal experimental testbeds for investigating macroscopic superpositions and microscopic thermodynamics. Integrating such levitated nanoparticles with photonic structures can enable strong coupling between their center-of-mass motion and guided photonic modes, facilitating enhanced control and probing of their motion. When coupling a particle to a photonic structure, such as a waveguide, the effects of fluctuations become prominent at nanoscales. In this work, we analyze the classical and quantized center-of-mass motion of a polarizable particle interacting with the fluctuations of the electromagnetic field in the presence of a medium. We derive a position localization master equation for the particle's quantized center of mass, and examine its classical center-of-mass momentum diffusion, elucidating correspondences between classical and quantum Brownian motion of polarizable particles near media. We study the decoherence rate of the particle in the presence of a planar surface as a function of temperature and distance from the surface, comparing it to common sources of decoherence. Our results are pertinent to experiments aimed at preparing levitated nanospheres in macroscopic quantum states and investigating their Brownian dynamics.

  PublisherDOI

• Added mass effect in coupled Brownian particles

  Physical review. E · 2025-05-01 · 1 citations

  articleSenior author

  The added mass effect is the contribution to a Brownian particle's effective mass arising from the hydrodynamic flow its motion induces. For a spherical particle in an incompressible fluid, the added mass is half the fluid's displaced mass, but in a compressible fluid its value depends on a competition between timescales. Here we illustrate this behavior with a solvable model of two harmonically coupled Brownian particles of mass m, one representing the sphere and the other representing the immediately surrounding fluid. The measured distribution of the Brownian particle's velocity, P(v[over ¯]), follows a Maxwell-Boltzmann distribution with an effective mass m^{*}. Solving analytically for m^{*}, we find that its value is determined by three relevant timescales: the momentum relaxation time, t_{p}; the harmonic oscillation period, τ; and the velocity measurement time resolution, Δt. In limiting cases of large timescale separations, m^{*} reduces to m or 2m. The model exhibits similar behavior when generalized to the case of unequal masses.

  PublisherDOI

• Continuous feedback protocols for cooling and trapping a quantum harmonic oscillator

  Physical review. E · 2025-01-28 · 4 citations

  articleOpen accessSenior author

  Quantum technologies and experiments often require preparing systems in low-temperature states. Here we investigate cooling schemes using feedback protocols modeled with a quantum Fokker-Planck master equation (QFPME) recently derived by Annby-Andersson et al. [Phys. Rev. Lett. 129, 050401 (2022)0031-900710.1103/PhysRevLett.129.050401]. This equation describes systems under continuous weak measurements, with feedback based on the outcome of these measurements. We apply this formalism to study the cooling and trapping of a harmonic oscillator for several protocols based on position and/or momentum measurements. We find that the protocols can cool the oscillator down to, or close to, the ground state for suitable choices of parameters. Our analysis provides an analytically solvable case study of quantum measurement and feedback and illustrates the application of the QFPME to continuous quantum systems.

  PublisherDOI

• Fluctuation theorems for autonomous work

  Proceedings of the National Academy of Sciences · 2025-12-12

  articleOpen access1st authorCorresponding

  Classical fluctuation theorems for work have been obtained theoretically, and verified experimentally, within a nonautonomous framework in which work is performed on a system of interest, [Formula: see text], by the external manipulation of a work parameter, such as a piston's position. Here, we obtain fluctuation theorems within an autonomous framework in which [Formula: see text] exchanges energy with a reversible work source, [Formula: see text]. The two subsystems, [Formula: see text] and [Formula: see text], interact with one another as they evolve under Hamiltonian or stochastic dynamics, without external intervention. In this setting, we must account for the backaction of [Formula: see text] on [Formula: see text], which is absent in the nonautonomous setting. We obtain autonomous versions of standard fluctuation theorems for work and entropy production. In each case, we argue, the autonomous fluctuation theorem reduces to its nonautonomous counterpart when [Formula: see text]'s inertia becomes infinitely large.

  PublisherOA PDFDOI

• Shortcuts to Adiabaticity across a Separatrix

  Physical Review Letters · 2025-04-17 · 1 citations

  articleSenior author

  Shortcuts to adiabaticity are strategies for conserving adiabatic invariants under nonadiabatic (i.e. fast-driving) conditions. Here, we show how to extend classical, Hamiltonian shortcuts to adiabaticity to allow the crossing of a phase-space separatrix-a situation in which a corresponding adiabatic protocol does not exist. Specifically, we show how to construct a time-dependent Hamiltonian that evolves one energy shell to another energy shell across a separatrix. Leveraging this method, we design an erasure procedure whose energy cost bound and fidelity do not depend on the protocol's duration.

  PublisherDOI

• Information Engine Fueled by First-Passage Times

  Physical Review Letters · 2025-10-02 · 2 citations

  articleOpen access

  Using a mechanical cantilever submitted to electrostatic feedback control, we investigate the thermodynamic properties of an information engine that extracts work from thermal fluctuations. The cantilever position is rapidly sampled and the feedback is triggered by the first passage of the system across a fixed threshold. The information ΔI associated with the feedback is based on the first-passage-time distribution. In this setting, we derive and experimentally verify two distinct fluctuation theorems that involve ΔI and give a tight bound on the work produced by the engine. Our results extend beyond the specific application to our experiment: we develop a general framework for obtaining fluctuation theorems and work bounds, formulated in terms of probability distributions of protocols rather than underlying measurement outcomes.

  PublisherOA PDFDOI

• Fluctuation theorems for autonomous work

  Maryland Shared Open Access Repository (USMAI Consortium) · 2025-12-23

  articleOpen access1st authorCorresponding

  Classical fluctuation theorems for work have been obtained theoretically, and verified experimentally, within a nonautonomous framework in which work is performed on a system of interest, S, by the external manipulation of a work parameter, such as a piston’s position. Here, we obtain fluctuation theorems within an autonomous framework in which S exchanges energy with a reversible work source, R. The two subsystems, R and S, interact with one another as they evolve under Hamiltonian or stochastic dynamics, without external intervention. In this setting, we must account for the backaction of S on R, which is absent in the nonautonomous setting. We obtain autonomous versions of standard fluctuation theorems for work and entropy production. In each case, we argue, the autonomous fluctuation theorem reduces to its nonautonomous counterpart when R’s inertia becomes infinitely large.

  PublisherOA PDFDOI

• Quantum Thermodynamics of Nonequilibrium Processes in Lattice Gauge Theories

  Physical Review Letters · 2024-12-19 · 8 citations

  articleOpen access

  A key objective in nuclear and high-energy physics is to describe nonequilibrium dynamics of matter, e.g., in the early Universe and in particle colliders, starting from the standard model of particle physics. Classical computing methods, via the framework of lattice gauge theory, have experienced limited success in this mission. Quantum simulation of lattice gauge theories holds promise for overcoming computational limitations. Because of local constraints (Gauss's laws), lattice gauge theories have an intricate Hilbert-space structure. This structure complicates the definition of thermodynamic properties of systems coupled to reservoirs during equilibrium and nonequilibrium processes. We show how to define thermodynamic quantities such as work and heat using strong-coupling thermodynamics, a framework that has recently burgeoned within the field of quantum thermodynamics. Our definitions suit instantaneous quenches, simple nonequilibrium processes undertaken in quantum simulators. To illustrate our framework, we compute the work and heat exchanged during a quench in a Z_{2} lattice gauge theory coupled to matter in 1+1 dimensions. The thermodynamic quantities, as functions of the quench parameter, evidence a phase transition. For general thermal states, we derive a simple relation between a quantum many-body system's entanglement Hamiltonian, measurable with quantum-information-processing tools, and the Hamiltonian of mean force, used to define strong-coupling thermodynamic quantities.

  PublisherOA PDFDOI

• Information engine fueled by first-passage times

  arXiv (Cornell University) · 2024-07-24 · 1 citations

  preprintOpen access

  Using a mechanical cantilever submitted to electrostatic feedback control, we investigate the thermodynamic properties of an information engine that extracts work from thermal fluctuations. The cantilever position is rapidly sampled and the feedback is triggered by the first passage of the system across a fixed threshold. The information $ΔI$ associated with the feedback is based on the first-passage-time distribution. In this setting, we derive and experimentally verify two distinct fluctuation theorems that involve $ΔI$ and give a tight bound on the work produced by the engine. Our results extend beyond the specific application to our experiment: we develop a general framework for obtaining fluctuation theorems and work bounds, formulated in terms of probability distributions of protocols rather than underlying measurement outcomes.

  PublisherOA PDFDOI

Recent grants

• Collaborative Research: Designing non-autonomous molecular machines

  NSF · $150k · 2009–2012

• Biomolecular Computational Thermodynamics: Strategies for Improved Efficiency

  NSF · $405k · 2009–2013

• Nonequilibrium Statistical Mechanics of Nanoscale Systems

  NSF · $435k · 2012–2015

• Dynamics and Thermodynamics of Nanoscale Systems

  NSF · $453k · 2022–2025

• Theoretical Studies in Far-From-Equilibrium Statistical Mechanics

  NSF · $270k · 2009–2013

Frequent coauthors

• Gavin E. Crooks

  20 shared

• Félix Ritort

  Universitat de Barcelona

  17 shared

• Carlos Bustamante

  University of California, Berkeley

  17 shared

• Eliane Trepagnier

  16 shared

• Jan Liphardt

  16 shared

• Carlos Floyd

  University of Chicago

  13 shared

• Diego M. Presman

  University of Buenos Aires

  13 shared

• Garegin A. Papoian

  University of Maryland, College Park

  13 shared

Labs

• Christopher Jarzynski LabPI

Awards & honors

• Fulbright Fellowship, Warsaw, Poland 1987-1988
• Raymond and Beverly Sackler Prize in the Physical Sciences T…
• Outstanding Referee for American Physical Society Journals 2…
• Fellow, American Physical Society 2009
• Fellow, American Academy of Arts and Sciences, 2016